[Chabs]

Speculation: GPU-based text rendering is typically going to be done using two triangles per glyph. So what they are seeing is probably not the allocation of the underlying texture storage, but the transient vertex buffer that contains the information of which glyph to render and where to render them.

[pcwalton]

Well, most GPU-based painting backends would try to recycle those VBOs to avoid reallocating them every frame. But it's hard to get all the heuristics right; cache invalidation is one of the two hard problems of computer science, after all…

[dahart]

Interesting, that sounds plausible and reasonable, except that the authors mention the minimum granularity of memory reporting is 128KB blocks. For this attack to work, the response to a keystroke has to reliably allocate more than 128KB every time. The vertex and index buffers for a pair of triangles is less than 100 bytes, right? So if only geometry were allocated, you'd only see measurable allocations every once in a while and not for every keystroke. What else might be getting allocated?